[unreadable] The rapid increase in the availability of genomic DMA sequences for many species has led to a vast array of genetically engineered products and treatments and driven biomedical research into a new era. Central to the progress of this research are microarrays, consisting of thousands of discrete genes printed as individual dots on a solid substrate. In operation, the microarrayed genes, also known as probes, hybridize comparatively to one of a number of mobile fluorescent tagged targets suspended in a buffer. By scanning the hybridized array for fluorescent tags, one can identify the target genes and for example compare gene expression patterns between normal and diseased tissues. A problem arises in the hybridization step. While one can investigate 30,000 genes at one time, it still takes overnight to hybridize a single microarray. In a situation such as SARS or bioterrorism, one would like to screen all the target genes and obtain the results instantaneously. Current hybridization technologies are expensive and the sensitivity is limited as a function of hybridization time. We propose to develop a technology compatible with all current microarray platforms that will provide rapid, sensitive, and cost effective hybridizations in about 10 minutes. We have run pilot studies on a prototype rapid hybridization system to generate preliminary data on printed microarrays. We have demonstrated efficient hybridization in 20 minutes. The projected cost of such a system is a fraction of today's costs and would allow wide spread deployment of this technology into medical research facilities and hospitals. The research proposed is aimed at improving the promising initial results and to showing commercial viability. [unreadable] [unreadable] [unreadable]